/*
 * Copyright (c) 2023. Baidu, Inc. All Rights Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *    http://www.apache.org/licenses/LICENSE-2.0
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and limitations under the License.
 */

package io.grpc.netty;

import static com.google.common.base.Preconditions.checkNotNull;

import com.google.common.base.Preconditions;
import com.google.errorprone.annotations.DoNotCall;
import io.grpc.Deadline;
import io.grpc.ExperimentalApi;
import io.grpc.Internal;
import io.grpc.ServerBuilder;
import io.grpc.ServerStreamTracer;
import io.grpc.internal.AbstractServerImplBuilder;
import io.grpc.internal.FixedObjectPool;
import io.grpc.internal.GrpcUtil;
import io.grpc.internal.InternalServer;
import io.grpc.internal.ObjectPool;
import io.grpc.internal.ServerImplBuilder;
import io.grpc.internal.ServerImplBuilder.ClientTransportServersBuilder;
import io.grpc.internal.SharedResourcePool;
import java.io.File;
import java.net.SocketAddress;
import java.util.List;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.TimeUnit;

/**
 * Builder for a server that services in-process requests. Clients identify the in-process server by its name.
 *
 * <p>The server is intended to be fully-featured, high performance, and useful in testing.
 *
 * <h2>Using JUnit TestRule</h2>
 * The class "GrpcServerRule" (from "grpc-java/testing") is a JUnit TestRule that creates a {@link InProcServer} and a
 * {@link io.grpc.ManagedChannel ManagedChannel}. This test rule contains the boilerplate code shown below. The classes
 * "HelloWorldServerTest" and "HelloWorldClientTest" (from "grpc-java/examples") demonstrate basic usage.
 *
 * <h2>Usage example</h2>
 * <h3>Server and client channel setup</h3>
 * <pre>
 *   String uniqueName = InProcessServerBuilder.generateName();
 *   Server server = InProcessServerBuilder.forName(uniqueName)
 *       .directExecutor() // directExecutor is fine for unit tests
 *       .addService(&#47;* your code here *&#47;)
 *       .build().start();
 *   ManagedChannel channel = InProcessChannelBuilder.forName(uniqueName)
 *       .directExecutor()
 *       .build();
 * </pre>
 *
 * <h3>Usage in tests</h3>
 * The channel can be used normally. A blocking stub example:
 * <pre>
 *   TestServiceGrpc.TestServiceBlockingStub blockingStub =
 *       TestServiceGrpc.newBlockingStub(channel);
 * </pre>
 */
@ExperimentalApi("https://github.com/grpc/grpc-java/issues/1783")
public final class InProcServerBuilder extends
    AbstractServerImplBuilder<InProcServerBuilder> {
    /**
     * Create a server builder that will bind with the given name.
     *
     * @param name the identity of the server for clients to connect to
     * @return a new builder
     */
    public static InProcServerBuilder forName(String name) {
        return forAddress(new InProcSocketAddress(checkNotNull(name, "name")));
    }

    /**
     * Create a server builder which listens on the given address.
     *
     * @param listenAddress The SocketAddress this server will listen on.
     * @return a new builder
     */
    public static InProcServerBuilder forAddress(SocketAddress listenAddress) {
        assert listenAddress instanceof InProcSocketAddress;
        return new InProcServerBuilder((InProcSocketAddress) listenAddress);
    }

    /**
     * Always fails.  Call {@link #forName} instead.
     */
    @DoNotCall("Unsupported. Use forName() instead")
    public static InProcServerBuilder forPort(int port) {
        throw new UnsupportedOperationException("call forName() instead");
    }

    private final ServerImplBuilder serverImplBuilder;
    final InProcSocketAddress listenAddress;
    int maxInboundMetadataSize = Integer.MAX_VALUE;
    ObjectPool<ScheduledExecutorService> schedulerPool = SharedResourcePool.forResource(GrpcUtil.TIMER_SERVICE);

    private InProcServerBuilder(InProcSocketAddress listenAddress) {
        this.listenAddress = checkNotNull(listenAddress, "listenAddress");

        final class InProcessClientTransportServersBuilder implements ClientTransportServersBuilder {
            @Override
            public InternalServer buildClientTransportServers(
                List<? extends ServerStreamTracer.Factory> streamTracerFactories) {
                return buildTransportServers(streamTracerFactories);
            }
        }

        serverImplBuilder = new ServerImplBuilder(new InProcessClientTransportServersBuilder());

        // In-process transport should not record its traffic to the stats module.
        // https://github.com/grpc/grpc-java/issues/2284
        serverImplBuilder.setStatsRecordStartedRpcs(false);
        serverImplBuilder.setStatsRecordFinishedRpcs(false);
        // Disable handshake timeout because it is unnecessary, and can trigger Thread creation that can
        // break some environments (like tests).
        handshakeTimeout(Long.MAX_VALUE, TimeUnit.SECONDS);
    }

    @Internal
    @Override
    protected ServerBuilder<?> delegate() {
        return serverImplBuilder;
    }

    /**
     * Provides a custom scheduled executor service.
     *
     * <p>It's an optional parameter. If the user has not provided a scheduled executor service when
     * the channel is built, the builder will use a static cached thread pool.
     *
     * @return this
     * @since 1.11.0
     */
    public InProcServerBuilder scheduledExecutorService(
        ScheduledExecutorService scheduledExecutorService) {
        schedulerPool = new FixedObjectPool<>(checkNotNull(scheduledExecutorService, "scheduledExecutorService"));
        return this;
    }

    /**
     * Provides a custom deadline ticker that this server will use to create incoming {@link Deadline}s.
     *
     * <p>This is intended for unit tests that fake out the clock.  You should also have a fake {@link
     * ScheduledExecutorService} whose clock is synchronized with this ticker and set it to
     * {@link #scheduledExecutorService}. DO NOT use this in production.
     *
     * @return this
     * @see Deadline#after(long, TimeUnit, Deadline.Ticker)
     * @since 1.24.0
     */
    public InProcServerBuilder deadlineTicker(Deadline.Ticker ticker) {
        serverImplBuilder.setDeadlineTicker(ticker);
        return this;
    }

    /**
     * Sets the maximum size of metadata allowed to be received. {@code Integer.MAX_VALUE} disables the enforcement.
     * Defaults to no limit ({@code Integer.MAX_VALUE}).
     *
     * <p>There is potential for performance penalty when this setting is enabled, as the Metadata
     * must actually be serialized. Since the current implementation of Metadata pre-serializes, it's currently
     * negligible. But Metadata is free to change its implementation.
     *
     * @param bytes the maximum size of received metadata
     * @return this
     * @throws IllegalArgumentException if bytes is non-positive
     * @since 1.17.0
     */
    @Override
    public InProcServerBuilder maxInboundMetadataSize(int bytes) {
        Preconditions.checkArgument(bytes > 0, "maxInboundMetadataSize must be > 0");
        this.maxInboundMetadataSize = bytes;
        return this;
    }

    InProcServer buildTransportServers(List<? extends ServerStreamTracer.Factory> streamTracerFactories) {
        return new InProcServer(this, streamTracerFactories);
    }

    @Override
    public InProcServerBuilder useTransportSecurity(File certChain, File privateKey) {
        throw new UnsupportedOperationException("TLS not supported in InProcessServer");
    }

    void setStatsEnabled(boolean value) {
        this.serverImplBuilder.setStatsEnabled(value);
    }
}
